From ec8e50e5786d3a876ebe3836063e7377833f861d Mon Sep 17 00:00:00 2001
From: "Jonathan D.A. Jewell" <6759885+hyperpolymath@users.noreply.github.com>
Date: Thu, 1 Oct 2026 09:01:18 +0100
Subject: [PATCH 1/2] docs: add Signed commits section to CONTRIBUTING

Owner ruling D218. See docs/SIGNING-POLICY.adoc in hyperpolymath/standards.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01WRvDivYwLSeVCJUrfjic3f
---
 .github/CONTRIBUTING.md | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)

diff --git a/.github/CONTRIBUTING.md b/.github/CONTRIBUTING.md
index f979e3f..16aa655 100644
--- a/.github/CONTRIBUTING.md
+++ b/.github/CONTRIBUTING.md
@@ -119,3 +119,20 @@ Footer: issue reference, e.g. Closes #123
 \[optional body\]
 
 \[optional footer\]
+
+### Signed commits
+
+Every commit that reaches the default branch must be signed; a ruleset refuses
+unsigned pushes. Estate policy:
+[SIGNING-POLICY](https://github.com/hyperpolymath/standards/blob/main/docs/SIGNING-POLICY.adoc).
+
+- **People and interactive agents** sign with an SSH key registered on GitHub
+  as a *signing* key (`gpg.format=ssh`, `user.signingkey=<key>.pub`,
+  `commit.gpgsign=true`). The committer email must be verified on that account.
+- **Apps, bots and workflows** never `git push` local commits. They write
+  through the API (`createCommitOnBranch` or the estate `signed-push` action)
+  so that GitHub signs each commit.
+- Merge PRs with **squash**. The ruleset checks every commit on the PR branch,
+  not just the result, so one unsigned commit blocks the merge. Re-create such a
+  branch with signed commits (`git cherry-pick -S`) and open a new PR.
+  Rebase-merge replays commits unsigned and is disabled.

From c7623da8d831d3913eff5b41f4f1926098b5b0be Mon Sep 17 00:00:00 2001
From: "Jonathan D.A. Jewell" <6759885+hyperpolymath@users.noreply.github.com>
Date: Thu, 1 Oct 2026 22:40:25 +0100
Subject: [PATCH 2/2] Update .github/CONTRIBUTING.md

Co-authored-by: coderabbitai[bot] <136622811+coderabbitai[bot]@users.noreply.github.com>
Signed-off-by: Jonathan D.A. Jewell <6759885+hyperpolymath@users.noreply.github.com>
---
 .github/CONTRIBUTING.md | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/.github/CONTRIBUTING.md b/.github/CONTRIBUTING.md
index 16aa655..c8d519c 100644
--- a/.github/CONTRIBUTING.md
+++ b/.github/CONTRIBUTING.md
@@ -134,5 +134,7 @@ unsigned pushes. Estate policy:
   so that GitHub signs each commit.
 - Merge PRs with **squash**. The ruleset checks every commit on the PR branch,
   not just the result, so one unsigned commit blocks the merge. Re-create such a
-  branch with signed commits (`git cherry-pick -S`) and open a new PR.
+  branch with signed commits (`git cherry-pick -S`) and update the existing PR
+  branch with `git push --force-with-lease`. Open a new PR only if that branch
+  cannot be updated.
   Rebase-merge replays commits unsigned and is disabled.